Hirumokin (蛭藻金)

(Ginza Coins Collection, Tokyo. Reproduction authorized. © All rights reserved.)

The Hirumokin represent a significant chapter in the history of Japanese coinage. Minted between 1501 and 1588, during a period of political transition and military unrest, these gold coins take their name from their resemblance to the leaves of the aquatic plant hirumo. Produced using advanced casting and engraving techniques, they were created by hammering gold sheets against stone until the desired shape was achieved. While similar in appearance to the better-known Ōban, Hirumokin were smaller and likely held lower monetary value. They are distinguished by their elongated shape and smooth surface, sometimes engraved with distinctive symbols upon request from local lords. The lack of standardization is evident in the variation in weight (up to 140 grams) and length (110–116 mm). Historical information remains limited, adding to the mystery surrounding these coins. In 1971, an archaeological discovery in Kōfu (Yamanashi Prefecture) uncovered numerous examples of Hirumokin and gold ingots, confirming the region's connection to Takeda Nobutomo, a key figure in the earliest phases of Japanese gold coinage.